Asked about the story, a White House spokeswoman said Obama had not made his decision about the Fed job.

Debate in Washington has focused on whether Obama will pick Summers or Fed Vice Chair Janet Yellen to succeed Ben Bernanke, whose term as head of the U.S. central bank expires in January. The appointment must be approved by the Senate.

Reports in the New York Times and Washington Post earlier this month suggested Obama was strongly inclined to pick Summers.

Republican Senator Johnny Isakson on Tuesday expressed concerns about a Summers nomination but stopped short of saying he would oppose him.

A number of senators — mostly Democrats — have criticized Summers for easing banking restrictions and not regulating derivatives when he was treasury secretary in the 1990s during the presidency of Bill Clinton.

The Nikkei said the White House is expected to announce the decision as early as late next week, after the Fed's rate-setting committee meets on Tuesday and Wednesday.